Elementary 2 math, will be speed! Thank you

The money required for 20 people to buy a group ticket = 20*10*yuan.

It is 180 yuan for 18 people to buy a full ticket, so it is cost-effective for 18 people to buy a collective ticket for 20 people.

There are x people, and the full fare is 10x yuan.

10x<=160 so x=16

So when there are 16 people, it is not a loss to buy a group ticket of 20 people.

1) Because of the 20-person group ticket 20% discount - 20 * 10 * 18 tourists buy a general ticket - 18 * 10 = 180 >160, so it is cheaper than buying a general ticket.

2) If there are less than 20 people, you will not lose money if you want to buy a group ticket for 20 people.

And because the group ticket of 20 people is 160

General admission is 10 yuan per person.

So at least 16 people are needed.

- This question is mainly based on "20% discount on group tickets for more than 20 people (including 20 people) = 160", and it is much easier to think about where the breakthrough is

1。It would have been 18*10=180

Pay 20*10* in cash

160 is less than 180

Cheap. x = 16 at least 16 people.

Buy 20 tickets for 160 yuan.

18 people, two remaining tickets sold for 16 yuan, and the actual cost was 144 yuan.

From the problem, the solution is that the length of the other right-angled side of the triangle is: (30 2-10 2)=20 2

So the area of the triangle s=10*20 2*1 2=100 2 because:|2x^2-32|+ 3y 2-234)=0 so 2x 2-32=0 gets:x=4 or x=-43y 2-234=0 get:

y=78 or y=- 78 because: |x^2-121|+(4y 2-9) 2=0So:x 2-121=0:

x=11 or x=-114y 2-9=0 yields: y=3 2 or y=-3 2

1. Another right-angled side = root number (30*30-10*10) = root number 800 = 20 root number 2

Area = 1 2 * 10 * 20 No. 2 = 100 No. 22, |2x^2-32|>=0

Root number 3y 2-234>=0

So: 2x 2-32 = 0, x = plus or minus 4

3y 2-243=0,y=plus/minus 9 (should be 243)3, the same:

x 2-121 = 0, x = plus or minus 11

4y 2-9=0, y=plus/minus 3 2

100 roots No. 2 square centimeters.

x = 4, y = root number 78

x=11,y=9/2

The other right-angled edge is the root number double the root number 2

Change number (30 square - 10 square meters) multiply 10 times change number 2

Just the answer?

k=4k=-1

k = -3 (this is not very certain).

1.Substituting (0,2) points to get k2=16, and k=plus or minus 4 2Let 1-k = 2 get k = -1 3Let 1-k = -1 3 get k = 4 3

x²+3x=x(x+3)

x+3)²+x+3)(2x-3)=（x+3）[(x+3)+(2x-3)]=4x(x+3)

Got it?? The characteristic of this type of question is that it is "made together" and I hope you can draw inferences from one another and master this type of question.

This proposition is written as if ......Then ......It is.

If the two angles are orthotonal angles, then the sum of the two angles is a flat angle.

The condition is: the two angles are adjacent complement angles.

The conclusion is that the sum of these two angles is a flat angle.

The sum of the adjacent complementary angles is a flat angle" condition is that the two angles are adjacent complementary angles

If the two angles are orthotonal angles, then the sum of the two angles is a flat angle.

It's pretty simple.

The triangle aeo and the triangle bcf are similar, the side length of the hypotenuse is already known, find the size of the angle and put it in the rectangle, 1, the root number 3, then one angle is 30 degrees, and the other is 60 degrees.

a (negative root 3, 1 2).

b（0,0）

c (Root of twoth.)

d (The focus of this question is to find the number of angles, and then find the correspondence between the side lengths, and the answer will be clear at a glance.)

as cb of, so than ab=of=1

In a right triangle a + b = c

OF side + CF side = OC side.

1 square + cf square = square of root number 3.

So cf = root number 2

So a(minus root 3,1 2).

b（0,0）

c (the root of the second half of the d(